Low water at Ostend also lasts for one hour.

Therefore, even if block-ships were sunk in the most favourable position the operation of making a passage by cutting away the upper works of the block-ships was not a difficult matter, and the Germans are a painstaking people.

This passage could be used for some time on each side of high water by vessels like destroyers drawing less than 14 feet, or submarines drawing, say, 14 feet.

The block would, therefore, be of a temporary and not a permanent nature, although it would undoubtedly be a source of considerable inconvenience.

At the same time it was realized that, although permanent blocking was not practicable, a temporary block would be of use, and that _the moral effect alone of such an operation would be of great value_.